It is known to construct tubular members for vehicles such as automotive vehicles. The tubular members are typically extruded from aluminum or magnesium and have a constant wall thickness. However, it is occasionally desirable to have a tubular member that has an increased stiffness, wherein the stiffness is increased away from the ends of the tubular member.
It is known to hydroform tubular components or members. Hydroformed tubular members are becoming increasingly popular in automotive body structural applications. During vehicle body manufacturing, many of the hydroformed tubular members are used in vehicle body and chassis applications. However, vehicle strength, stiffness, and/or impactworthiness often necessitate the need for local areas of structural reinforcement to meet their design goals.
It is further known to make “T” fittings such as for plumbing tube connectors using an axial feed hydroforming process. In this process, a die is constructed to have two opposing end seals and a piston situated in a center and perpendicular to the straight cylindrical cavity of the die. A straight tubular member is placed in the die. The die is closed and the ends seals are brought into contact with the ends of the tubular member. Fluid is filled into the tubular member. The hydroforming process proceeds by progressively increasing the internal fluid pressure in the tubular member while the end seals are pushed toward one another, compressing the tubular member axially. Concurrent with the end seals moving toward each other, the central piston, which was initially flush with the die cavity wall, is progressively retracted to allow a sidewall of the tubular member to bulge into a shaft of the piston and create a “T” shape of the T fitting. The resulting hydroformed dome of the T fitting will have a portion of its sidewall that is straight and of length in contact with the shaft of the central piston. However, there are circumstances in which the requirements for length of the straight side of the hydroformed dome of the “T” fitting is inadequate for sufficient overlap of an attaching tubular member to produce a reliable lap weld condition.
As a result, it is desirable to provide a method of increasing a straight sidewall of a dome on a T fitting. It is also desirable to provide a hydroformed “T” shaped tubular member having sufficient overlap for an attaching tubular member to produce a reliable lap weld condition. Therefore, there is a need in the art to provide a new hydroformed tubular member and cost effective method that meets at least one of these desires.